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Volume 3, Issue 1
Displaying 1-7 of 7 articles from this issue
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Morisaburô TAUTI1934 Volume 3 Issue 1 Pages 1-4
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDownload PDF (195K) -
Syôkiti KAMIYA1934 Volume 3 Issue 1 Pages 5-7
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSAs the meshes are not uniform in any net, the tensions on their arms cannot be equal to each other, though the net is stretched as uniformly as possible. To know the actual value of the dispersion of tension caused by the irregularity of meshes, the author has studied Pearson's coefficient of variation V with cotton nets.
In the net, spread uniformly on a vertical rectangular iron frame 1.5m high and 1.0m broad, and loaded uniformly on its bottom with some wèights (40.-80.kg), the tension on each arm is measured one by one with an apparatus as shown in Fig. 1. The measurement with this apparatus is affected by the inaccuracy due to the construction of the latter, and moreover gives too small values of the tension when the arm runs as (1) in Fig. 2, and too large ones when it runs as (2). The tention, being affected by the friction at the vertical edges of the frame, varies systematically from the top to the bottom with the step of the meshés. Deducting the variances caused by the various hindrances like that, the author has got the following relation:
(V/100)2=σ12+σ22/2m2(1-r2)-(v/100)2,
where σ1, σ2 are the standard deviations of the tension calculated seperately with the cords running as (1) and with those running as (2), m is the arithmetic mean of the ten ?? ion, r is the correlatian ceofficient between the tension and the step of meshes, and v is the coefficient of variation in per cent which is due to the errors of observation. Considering both the sampling error and the error of v2,
σv=1/4V√2V4/N{1+2(V/100)2}+σ2v2,
where N is the number of arms observed.
The result of calculation, which is tabulated in Tab. 1, indicates that the values of V do not differ from each other among the nets having knots of the same kind, and the weighted mean of V is, as in Tab. 2,
8.4±0.19 (standard error) for the net of trawl knots,
and 5.6±0.21 ( ?? ) for the net of flat knots.View full abstractDownload PDF (712K) -
I. The Cods, Gadus macroccphalus TILESIUS and Theragra chalcogramma (PALLAS)Yasuo SUYEHIRO1934 Volume 3 Issue 1 Pages 8-16
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe writer examined the digestive tract and its contents to study the feeding habit of adult forms of two kinds of cods, viz., Gadus macrocephalus (J. N. Madara) and Theragra chalcogramma (J. N. Suketô), both of which were collected during the summer of 1933 in Bristol Bay. The former species being, as is shown in the Table 2, exceedingly voracious, feeds greedily upon the bottom creatures, such as crabs, sand-living worms etc.. Fishes, such as Suketô and several flat-fishes, are also very often eaten by the cod. The fact that a cod feeds on the other kind of cods is worthy of attention and noted here again, although similar cases have been observed and reported by some authors (3, 6, 7, 8, 9, 10, 11). The latter species, on the contrary, as is shown in the Table 4, is poor feeder and feeds upon creatures of small size and the plankton, such as copepods and small shrimps.
Thus, these two cods show essential difference in their feeding habit. As the cause of such a difference, the fact may be noted that the former species lives near the bottom of the sea, while the latter in the middle or the upper layer of the water. And at the same time, it would be worth mentioning that the construction of the digestive systems of the two species shows different features; in the former species the apparatuses for seizing the food (the mouth, the teeth and the tongue) and the organs of digestion (the stomach, the digestive mucous membrane, the vascular supply on the stomach and the pyloric appendages) are all well developed, while in the latter not so. It is also of interest that the former species has coarse gill-rakers which cannot collect fine food such as the plankton, while the latter has fine ones which are favourable to retain it.View full abstractDownload PDF (1399K) -
Yarokurô YAMAMURA1934 Volume 3 Issue 1 Pages 17-22
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSLake Inawasiro is located at the north latitude 37°30' and the east longitude 140°05' and is 514m high above the sea-level. It has the coast 56.09km long, the area of 103.64km2 and the maximum depth of 102m. On the occasion of the great explosion of the volcano Bandai in 1888, all the fishes in the lake were killed and the lake has become barren. Over twenty years after that time the Hukusima Fisheries Experimental Station made a chemical analysis of the lake water, which proved to be no more unusual. Since 1908 Hukusima Fisheris Experimental Station has taken charge of the fish cultual experiment of trouts (Oncorhynchus nerka and Salvelinus kundscha) in this lake, liberating to it 125, 300-3, 200, 000 young every year. Compared with these, however, only 550-1, 800 adults a year are caught in the rivers around the lake. Why is the productivity so poor as this?
To answer this question, the present author made an investigation last summer (1933) on the chemical properties1) of the water and the distribution of plankton in this lake.
The Nagase River, rising from the northern foot of Mt. Bandai, supplies the largest part of the inflow to this lake. It discharges water from the lakes of Hibara, Akimoto and Onogawa mixed with the highly acidic water of a branch called Su-gawa. By dint of inflow of the acidic water the whole mass of the lake water is markedly acidified showing the fall in pH-values to 2.8 at the inlet and 5.5 at the outlet (Fig. 1). In Fig. 1 the direction of the flow of this acidic water over the lake, inferred from the isolines of pH-values, is indicated by the arrows. The results of the chemical analysis of surface-samples from different positions are tabulated in Tab. 1. We know that the phosphate and the nitrate are extremely poor, while the sulphate is comparatively rich.
The composition of the plankton in several parts of the lake collected by horizontal hauls through 400m in the surface-layer is shown in Tab. 2. The plankton is generally very poor in its density except at the stations XII, XIII, XIV and XV in the shallow littoral zone which is fed by the fresh water from the skirts of Mt. Bandai raising the pH-value to 6.0 to 8.0. The relation between the pH-values and the density of the plankton is given in Tab. 3, whence we can see that the zoo-plankton develops hardly at the pH-value of 5.3, while the phyto-plankton distributes in a wider range. Both the zoo-plankton and the phyto-plankton grow most favourably at pH of 7.0 to 8.0.View full abstractDownload PDF (362K) -
Eiji KAJIYAM1934 Volume 3 Issue 1 Pages 23-24
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe live parwn, Penaeus japonicus, is transported in Japan either in aerated sea-water or in dry rice-husks. When packed with dry rice-husks in a glass-cup (4-6cm im diameter, and 10cm in height) and put in a water-tank regulated at various temperatures, the prawns from a habitat fo lower temperature were found to live longer than those from a place of higher temperature (Fig. 1). The temperature range from 13.9°-24.7°C and the salinity variations from 1.016-1.0252 (in density) of the running sea-water, which was supplied to the prawns in a glass vessel, did not change the vitality of the experimental animals (Table 1).View full abstractDownload PDF (108K) -
I. On Amorphous Mass FormationYukio GOTÖ1934 Volume 3 Issue 1 Pages 25-30
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSMany observations have been done on pleomorphism of bacteria, but they are far from complete. Since 1931 I have been occupied with experiments relating to this problem and found amorphous mass formation in Flavobacterium A in hanging drop cultures.
Such mass formation results from agglutination and subsequent fusion of a number of cells which are either descendants of a single cell or clumping ones of multiple origins. I observed also that minute particles germ out from the amorphous mass to assume the ordinary form again.
Such mass-formation has been observed by me in Pseudomonas fluorescens, Pseudomonas ovalis, Achromobacter multistriatum, Serratia marcescens, Escherichia coli, Eberthella typhi, and Salmonella paratyphi.View full abstractDownload PDF (473K) -
Masao FUJIMOTO, Takaharu YAMAMOTO1934 Volume 3 Issue 1 Pages 31-36
Published: May 15, 1934
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSIn January 1928, a large dam was constructed in the River Somjingnag (Senshinko), Southern Korea (Fig. 1). The water-reservoir thus formed measures abont 70.2km in circumference, 7.1 square km in area, and 28.8m in maximum depth. The dam entirely kept the anadromous salmoid fish, Ayu (Plecoglossus altivelis), from reaching the upper streams. In autumn of 1928 and 1929, a considerably large amount of the artificially fertilized eggs of this fish were put by the present authors in the reservoir. From summer of 1931 on, the Ayu is found land locked there as is the case with that in Lake Biwa and is propagating there well in spite of rather low temperature of the water (See Figs. 3 and 4).View full abstractDownload PDF (388K)
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